Question

question 20 (0.5 points)
if blood travels from an arteriole through a metarteriole and directly into a venule, what does this imply?
○ the arteriole dilated.
○ the venule dilated.
○ pre- capillary sphincters are closed.
○ pre- capillary sphincters are open.

Explanation:

To solve this, we analyze blood flow in the microcirculatory system. Normally, blood from arterioles flows through capillaries (regulated by pre - capillary sphincters) before entering venules. If blood goes from an arteriole through a metarteriole directly into a venule, it means the pre - capillary sphincters (which control blood entry into capillaries) are closed. This is because when pre - capillary sphincters are closed, blood takes the shortcut through metarterioles to venules, bypassing the capillaries. Arterioles dilating would increase blood flow to capillaries (if sphincters are open), and venule dilation is about venous return, not this bypass mechanism. So the correct implication is that pre - capillary sphincters are closed.

Answer:

Pre - capillary sphincters are closed.